Table Of ContentAN ABSTRACT OF THE THESIS OF
Hazel L. Owens for the degree of Master of Science in Water Resources Science
presented on June 17, 2013.
Title: Relationships Between Stream Discharge and Cutthroat Trout Abundance at
Multiple Scales in Managed Headwater Basins of Western Oregon
Abstract approved:
_____________________________________________________________________
Arne E. Skaugset
Relationships between resident cutthroat trout (Oncorhynchus clarkii clarkii) and six
hydrologic indices were investigated using correlation analysis in two experimental
headwater catchments in the foothills of the Cascade Mountains of western Oregon.
This investigation was to determine if characteristics of discharge explained inter-
annual variability in trout abundance. Eight years of continuous discharge and annual
abundance data collected from two contiguous watersheds from the Hinkle Creek
Paired Watershed Study were used for this study. Density-discharge relationships
were identified separately in the watershed actively managed for timber harvest and in
the control watershed. Correlation was determined at multiple stream segments and at
the watershed scale to assess the roles of spatial scale and network location on the
detectability of density-discharge relationships. A method for improving the spatial
coupling of density and discharge measurements within the stream network was also
investigated.
No correlations (r ≤ ǀ0.50ǀ) between hydrologic indices and age-1+ trout density in
either watershed were found. Two hydrologic indices were related to the density of
age-0 trout: maximum annual discharge (r = 0.780) in the control watershed and Q90
summer discharge (r = 0.697) in the treated watershed. The correlation between the
density of age-0 trout and each of these two indices were similar across individual
stream segments, but variability in the magnitude of the correlation suggests that
network location plays a key role in facilitating processes that link density and
discharge. Variability in the magnitude of the correlation across stream segments also
influenced the detectability and interpretability of relationships observed at the extent
of a watershed and at the extent of a stream segment. These results indicate that
researchers interested in understanding the dynamics of cutthroat trout abundance
should consider the effects of discharge on inter-annual variability in abundance of
different age classes and the role of network location on the detectability of
relationships.
©Copyright by Hazel Owens
June 17, 2013
All Rights Reserved
Relationships Between Stream Discharge and Cutthroat Trout Abundance at Multiple
Scales in Managed Headwater Basins of Western Oregon
by
Hazel L. Owens
A THESIS
Submitted to
Oregon State University
in partial fulfillment of
the requirements for the
degree of
Master of Science
Presented June 17, 2013
Commencement June 2014
Master of Science thesis of Hazel L. Owens presented on June 17 2013.
APPROVED:
Major Professor, representing Water Resources Science
Director of the Department of Water Resources
Dean of the Graduate School
I understand that my thesis will become part of the permanent collection of Oregon
State University libraries. My signature below authorizes release of my thesis to any
reader upon request
Hazel L. Owens, Author
ACKNOWLEDGEMENTS
I would like to thank my major advisor Arne Skaugset, for his direction and guidance
over the last two years. I am ever grateful to him for his willingness to take a card-
carrying biologist under his wing and spend the next two years training her in the ways
of forest hydrology. His open-door policy, patience, empathy, sense of humor, and
endless words of wisdom have taught me important lessons on how to be a productive
member of the scientific community. For two years of funding, a fun summer of
tromping through Hinkle Creek, and the many hours spent in his office talking about
science, corgis, and the other important things in life, I owe him my sincere
appreciation.
I would also like to thank Doug Bateman for providing me with the fisheries datasets
and access to his incredible wealth of knowledge regarding Hinkle Creek, cutthroat
trout, and stream ecology. For many reasons, this project would not have been
possible without Doug Bateman. I also want to express sincere gratitude to the
statistics dream team, Lisa Ganio and Ariel Muldoon, for helping me with my
statistical analysis. Lisa and Ariel both have an inspirational ability to think critically,
ask important questions, and see the big picture. My demand on their time was not
trivial and I appreciate every minute of it.
Stanley Gregory provided me with the foundational knowledge for understanding this
interdisciplinary project. I want to thank Stan, not only for his role as a committee
member, but for being an incredible teacher. I also want to thank my GCR, Steve
Tesch, for being the nicest guy roaming the halls of the College of Forestry and for his
sincere interest in my project and personal well-being.
Amy Simmons, Alex Irving, and Dave Leer are also recipients of my sincere gratitude
for their roles in project support, data collection, processing, and management. I
would also be remiss in not thanking a number of individuals who intellectually
supported this project in one way or another at different stages, including Rebecca
Flitcroft, Kelly Burnett, and Jason Dunham.
Finally, I have to thank my mom for being my biggest fan. My mother unwittingly
reminds me that life is funny and it deserves to be laughed at as loud and obnoxiously
as possible. I also thank the rest of my family, old friends, and new friends for their
love, support, and patience over the last two years. You guys are the greatest.
TABLE OF CONTENTS
Page
CHAPTER 1- INTRODUCTION .................................................................................. 1
RESEARCH CONTEXT ............................................................................................ 1
OBJECTIVES ............................................................................................................. 2
CHAPTER 2- LITERATURE REVIEW ....................................................................... 4
DISCHARGE ............................................................................................................. 4
FOREST MANAGEMENT CONTEXT .................................................................... 7
SPATIOTEMPORAL CONTEXT ............................................................................. 8
CHAPTER 3- METHODS ........................................................................................... 14
STUDY AREA ......................................................................................................... 14
DATA COLLECTION ............................................................................................. 23
PARAMETER DEVELOPMENT ........................................................................... 24
DATA ANALYSIS .................................................................................................. 35
CHAPTER 4- RESULTS ............................................................................................. 46
SPATIAL INCONGRUENCE ................................................................................. 46
WATERSHED SCALE ANALYSIS ....................................................................... 53
STOCK-RECRUITMENT & COHORT STRENGTH ............................................ 57
STREAM SEGMENT level ANALYSIS ................................................................ 58
CHAPTER 5- DISCUSSION....................................................................................... 69
SPATIAL INCONGRUENCE ................................................................................. 69
WATERSHED LEVEL ANALYSIS ....................................................................... 70
STREAM SEGMENT LEVEL ANALYSIS ............................................................ 92
TABLE OF CONTENTS (Continued)
Page
CHAPTER 6- CONCLUSIONS .................................................................................. 96
BIBLIOGRAPHY ...................................................................................................... 100
APPENDICES ........................................................................................................... 108
APPENDIX A- GLOSSARY OF TERMS ............................................................. 108
APPENDIX B- ABUNDANCE DATA ................................................................. 111
APPENDIX C- HYDROLOGIC DATA ................................................................ 116
APPENDIX D- SPATIAL INCONGRUENCE ..................................................... 117
Description:/s) from the North Umpqua River at Winchester, .. less than 200 m length and draw inference to a spatial extent that extends beyond the extent (1–100 km), an extent that encompasses the important aspects of life history, .. stream segment level, but the HCPWS provided an opportunity to calculate
